did you try correcting the current output and input path?
if this is your problem try fixing it.
but otherwise, the only other problem i have ever had with that sort of thing is if you put the button prefix (BTN, DISBTN etc.) behind the name of the icon before you convert it with the program. it automatically puts the prefix to the converted icon. but if it is put on before you convert it with the program it won't recognize it as an image file. leading it to be unknown and not found by the program.
other than that i am unsure of what is wrong with the program. if any further questions are needed then you should take it up with the creator of the program, Shadow Daemon.
~Dentothor